1. Field of the Invention
The present disclosure is directed to a system and a method for controlling operating temperatures of integrated circuits (ICs). In particular, the present disclosure utilizes machine learning techniques to control temperatures of the ICs.
2. Related Art
Package-on-package (POP) solutions are implemented by packaging a silicon wafer of a first integrated circuit along with (e.g., on top of) a silicon wafer of a second integrated circuit, the first integrated circuit being electrically connected to the second integrated circuit. The use of POP solutions is desirable because it eliminates the need for long electrical connections (e.g., wirebonds, traces, etc.) to electrically connect the first integrated circuit with the second integrated circuit, thereby reducing latency between the two integrated circuits. For example, an external memory circuit can be packaged on top of a baseband circuit to form a POP solution. However, conventionally, such a POP solution is undesirably designed to have a lower operating device temperature limit with respect to the operating device temperature of the individual baseband circuit. This is because, during operation, the relatively lower device temperature of the external memory circuit is adversely impacted by the relatively higher device temperature of the baseband circuit. In particular, the baseband circuit may be capable of operating at high frequencies (>2 GHz), and, therefore, the baseband circuit may generate a large amount of heat which would need to be dissipated in the POP solution. This large amount of heat may raise the device temperature of the POP solution to be greater than the relatively lower device temperature limit of the external memory circuit. This causes damage to the external memory circuit. Further, the frequent elevation of the external memory's device temperature closer to its limit contributes to accelerated aging of the external memory circuit, resulting in undesirable higher leakage currents. Thus, to minimize the above adverse effects to the external memory circuit, the baseband circuit is designed to function at an operating frequency which is lower than the operating frequency at which the baseband circuit is capable of operating. This prevents the baseband circuit from generating the large amount of heat that adversely impacts the external memory circuit. However, even though the above adverse effects to the external memory circuit are minimized, the limiting of the operating frequency of the baseband circuit to control the device temperature of the POP solution is undesirable because it reduces the overall performance of the POP solution.
Also, other conventional techniques employed to control the device temperatures of the individual integrated circuits in POP solutions are not optimum. For example, one conventional technique is a reactive technique (as opposed to predictive) and relies on thermal throttling to control the device temperature. In this reactive technique, a processor is allowed to run at full capacity. However, when a measured operating temperature of the processor exceeds a given thermal limit, the running capacity of the processor is reactively curtailed to reduce the operating device temperature of the same. This reactive technique is not optimum because it degrades the performance of the processor and provides a limited time period to prevent a thermal runaway condition. Further, this reactive correction requires a throttling system that requires significant and periodic calibrations.
Another known temperature control technique requires determining a highest performance condition of the processor based on an application profile information of a given application, and reactively re-configuring the processor for thermal safety when the highest performance condition is observed. Again, this technique is not optimum because it is specific to an application, and must be duplicated for every application before being executed on the processor. Further, implementation of this technique during operation can be very complex (due to the involved mathematics) depending upon the various processes required to be run by each application.